The health status of the oral cavity is in large part influenced by constituents of saliva. The principal function of salivary glands is the production of this complex fluid. To study the mechanisms controlling secretion of salivary components we have utilized both in vitro and in vivo animal preparations. As probes of secretory events we have focused our studies primarily on pertubations in neurotransmitter mediated control of gland secretory functions that occur with normal aging. Secondly, we have studied mechanists events associated with two types of therapy-induced salivary gland dysfunctions; treatment by x-radiation and by phenothiazine. During the present reporting period we have focused efforts on (1) the mechanisms of Ca++ mobilization, in intact salivary gland cells and in isolated basolateral plasma membrane vesicles; (2) Alpha1-adrenergic receptor regulated secretory events; (3) the handling of 99mTc by salivary cells; (4) development of a model of chronic radiation damage to salivary glands; and (5) characterizing the mechanism of phenothiazine-induced salivary gland dysfunctions.